Chaughdia is calculated from 6:00 AM local Sunrise time and 6:00 PM Sunset time. If the Sun rise and Sunset time is differerent at particular place then one can calculate from that time .Each choghadia period is for one hour and thirty minutes (1.30 Hours) so one can calculate from particular sunrise time , eight,(8) choghadia are day time and eight (8) choghadia are night time so that total choghadia are 16 in all day and night time.